Even in clouds over mountains they were spotted microplastics and it appears they may even affect the weather, according to research published in the American Chemical Society’s journal ACS Environmental Science & Technology Letters.

Microplastics, fragments of plastic smaller than five millimeters, come from millions of items used every day, such as clothing, packaging and car tires.

The research team collected samples from the clouds on top of Mount Tai in eastern China.

After analyzing the samples, they found that denser clouds and low-altitude clouds contained greater amounts of microplastics.

Microplastics tended to be less than 100 micrometers in length, although some were up to 1,500 micrometers long.

The older, rougher particles had more lead, mercury and oxygen attached to their surfaces, which the researchers say could facilitate cloud growth.

To investigate where the particles in the clouds came from, the researchers developed computer models to approximate how the particles traveled to Mount Tai.

The models suggested that the main source of debris was airflow from densely populated inland areas rather than the ocean or other nearby mountains.